Water Balance Assessment for the Clarence-Moreton Bioregion, PDF

Water balance assessment for the Clarence-Moreton bioregion Product 2.5 from the Clarence-Moreton Bioregional Assessment

31 January 2017

A scientific collaboration between the Department of the Environment and Energy, Bureau of Meteorology, CSIRO and Geoscience Australia The Bioregional Assessment Programme The Bioregional Assessment Programme is a transparent and accessible programme of baseline assessments that increase the available science for decision making associated with coal seam gas and large coal mines. A bioregional assessment is a scientific analysis of the ecology, hydrology, geology and hydrogeology of a bioregion with explicit assessment of the potential impacts of coal seam gas and large coal mining development on water resources. This Programme draws on the best available scientific information and knowledge from many sources, including government, industry and regional communities, to produce bioregional assessments that are independent, scientifically robust, and relevant and meaningful at a regional scale. The Programme is funded by the Australian Government Department of the Environment and Energy. The Department of the Environment and Energy, Bureau of Meteorology, CSIRO and Geoscience Australia are collaborating to undertake bioregional assessments. For more information, visit http://www.bioregionalassessments.gov.au. Department of the Environment and Energy The Office of Water Science, within the Australian Government Department of the Environment and Energy, is strengthening the regulation of coal seam gas and large coal mining development by ensuring that future decisions are informed by substantially improved science and independent expert advice about the potential water related impacts of those developments. For more information, visit https://www.environment.gov.au/water/coal-and-coal-seam-gas/office-of-water-science. Bureau of Meteorology The Bureau of Meteorology is Australia’s national weather, climate and water agency. Under the Water Act 2007, the Bureau is responsible for compiling and disseminating Australia's water information. The Bureau is committed to increasing access to water information to support informed decision making about the management of water resources. For more information, visit http://www.bom.gov.au/water/. CSIRO Australia is founding its future on science and innovation. Its national science agency, CSIRO, is a powerhouse of ideas, technologies and skills for building prosperity, growth, health and sustainability. It serves governments, industries, business and communities across the nation. For more information, visit http://www.csiro.au. Geoscience Australia Geoscience Australia is Australia’s national geoscience agency and exists to apply geoscience to Australia’s most important challenges. Geoscience Australia provides geoscientific advice and information to the Australian Government to support current priorities. These include contributing to responsible resource development; cleaner and low emission energy technologies; community safety; and improving marine planning and protection. The outcome of Geoscience Australia’s work is an enhanced potential for the Australian community to obtain economic, social and environmental benefits through the application of first class research and information. For more information, visit http://www.ga.gov.au. ISBN-PDF 978-1-925315-38-7 Citation Cui T, Gilfedder M, Pickett T, Rassam D, Viney N, Crosbie R, Peeters L, Raiber M, Wang B and Hartcher M (2016) Water balance assessment for the Clarence-Moreton bioregion. Product 2.5 from the Clarence-Moreton Bioregional Assessment. Department of the Environment and Energy, Bureau of Meteorology, CSIRO and Geoscience Australia, Australia. http://data.bioregionalassessments.gov.au/product/CLM/CLM/2.5. Authorship is listed in relative order of contribution. Copyright

© Commonwealth of Australia 2016 With the exception of the Commonwealth Coat of Arms and where otherwise noted, all material in this publication is provided under a Creative Commons Attribution 3.0 Australia Licence http://www.creativecommons.org/licenses/by/3.0/au/deed.en. The Bioregional Assessment Programme requests attribution as ‘© Commonwealth of Australia (Bioregional Assessment Programme http://www.bioregionalassessments.gov.au)’. Disclaimer The information contained in this report is based on the best available information at the time of publication. The reader is advised that such information may be incomplete or unable to be used in any specific situation. Therefore decisions should not be made based solely on this information or without seeking prior expert professional, scientific and technical advice. The Bioregional Assessment Programme is committed to providing web accessible content wherever possible. If you are having difficulties with accessing this document please contact [email protected]. Cover photograph Rainforest waterfall in Border Ranges National Park, NSW, 2008 Credit: Liese Coulter, CSIRO

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Contents

Contributors to the Technical Programme ...... iv

Acknowledgements ...... vi

Introduction ...... 1

The Bioregional Assessment Programme ...... 1 Methodologies ...... 3 Technical products ...... 5 About this technical product ...... 8 References ...... 8

1.5.1 Methods ...... 11

1.5.1.1 Spatial and temporal extent of the water balances ...... 11 1.5.1.2 Water balance uncertainty ...... 14 References ...... 15 Datasets ...... 16

1.5.2 The water balances ...... 17

1.5.2.1 Water balance based on the AWRA-L model ...... 17 1.5.2.1.1 Water balance for Eden Creek (model node CLM002) ...... 18 1.5.2.1.2 Water balance for Shannon Brook above Yorklea (model node CLM007) ...... 19 1.5.2.1.3 Water balance for Richmond River above Casino (model node CLM008) ...... 19 1.5.2.1.4 Water balance for Richmond River above Kyogle (model node CLM014) ...... 20 1.5.2.2 Water balance based on groundwater model ...... 21 1.5.2.3 Gaps ...... 24 References ...... 24 Datasets ...... 25

Glossary ...... 26

Water balance assessment for the Clarence-Moreton bioregion | i

Figures

Figure 1 Schematic diagram of the bioregional assessment methodology ...... 2

Figure 2 Technical products and submethodologies associated with each component of a bioregional assessment ...... 6

Figure 3 Location of model nodes for surface water balance terms for the Clarence-Moreton bioregion ...... 13

ii | Water balance assessment for the Clarence-Moreton bioregion

Tables

Table 1 Methodologies ...... 4

Table 2 Technical products delivered for the Clarence-Moreton bioregion ...... 7

Table 3 Computing approaches of water balance terms in the surface water model for the Clarence-Moreton bioregion ...... 14

Table 4 Computing approaches of water balance terms in the groundwater model for the Clarence-Moreton bioregion ...... 15

Table 5 Surface water balance totals at Eden Creek (model node CLM002). Results summarise the range in the 30 groundwater model runs for each of the three climate periods modelled in the Clarence-Moreton bioregion ...... 18

Table 6 Surface water balance totals at Shannon Brook above Yorklea (model node CLM007). Results summarise the range in the 30 groundwater model runs for each of the three climate periods modelled in the Clarence-Moreton bioregion ...... 19

Table 7 Surface water balance totals at Richmond River above Casino (model node CLM008). Results summarise the range in the 30 groundwater model runs for each of the three climate periods modelled in the Clarence-Moreton bioregion ...... 20

Table 8 Surface water balance totals at Richmond River above Kyogle (model node CLM014). Results summarise the range in the 30 groundwater model runs for each of the three climate periods modelled in the Clarence-Moreton bioregion ...... 21

Table 9 Mean annual groundwater balance for the entire groundwater model domain for the three reporting periods in the Clarence-Moreton bioregion (ML/year) ...... 23

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Contributors to the Technical Programme

The following individuals have contributed to the Technical Programme, the part of the Bioregional Assessment Programme that undertakes bioregional assessments.

Role or team Contributor(s) Assistant Secretary Department of the Environment and Energy: Matthew Whitfort Programme Director Department of the Environment and Energy: Anthony Swirepik Technical Programme Director Bureau of Meteorology: Julie Burke Projects Director CSIRO: David Post Principal Science Advisor Department of the Environment and Energy: Peter Baker Science Directors CSIRO: Brent Henderson Geoscience Australia: Steven Lewis Integration Bureau of Meteorology: Richard Mount (Integration Leader) CSIRO: Becky Schmidt Programme management Bureau of Meteorology: Louise Minty CSIRO: Paul Hardisty, Warwick McDonald Geoscience Australia: Stuart Minchin Project Leaders CSIRO: Alexander Herr, Kate Holland, Tim McVicar, David Rassam Geoscience Australia: Tim Evans Bureau of Meteorology: Natasha Herron Assets and receptors Bureau of Meteorology: Richard Mount (Discipline Leader) Department of the Environment and Energy: Glenn Johnstone, Wasantha Perera, Jin Wang Bioregional Assessment Bureau of Meteorology: Lakshmi Devanathan (Team Leader), Derek Chen, Information Platform Trevor Christie-Taylor, Melita Dahl, Angus MacAulay, Christine Price, Paul Sheahan, Kellie Stuart, Carl Sudholz CSIRO: Peter Fitch, Ashley Sommer Geoscience Australia: Neal Evans Communications CSIRO: Helen Beringen, Department of the Environment and Energy: Amanda Forman, John Higgins, Lea Locke, Milica Milanja Geoscience Australia: Michelle McGranahan Coordination Bureau of Meteorology: Brendan Moran, Eliane Prideaux, Sarah van Rooyen CSIRO: Ruth Palmer Department of the Environment and Energy: Anisa Coric, Lucy Elliott, James Hill, Andrew Stacey, David Thomas, Emily Turner Ecology CSIRO: Anthony O'Grady (Discipline Leader), Caroline Bruce, Tanya Doody, Brendan Ebner, Craig MacFarlane, Patrick Mitchell, Justine Murray, Chris Pavey, Jodie Pritchard, Nat Raisbeck-Brown, Ashley Sparrow Geology CSIRO: Deepak Adhikary, Emanuelle Frery, Mike Gresham, Jane Hodgkinson, Zhejun Pan, Matthias Raiber, Regina Sander, Paul Wilkes Geoscience Australia: Steven Lewis (Discipline Leader)

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Role or team Contributor(s) Geographic information CSIRO: Jody Bruce, Debbie Crawford, Dennis Gonzalez, Mike Gresham, systems Steve Marvanek, Arthur Read Geoscience Australia: Adrian Dehelean, Joe Bell Groundwater modelling CSIRO: Russell Crosbie (Discipline Leader), Tao Cui, Warrick Dawes, Lei Gao, Sreekanth Janardhanan, Luk Peeters, Praveen Kumar Rachakonda, Wolfgang Schmid, Saeed Torkzaban, Chris Turnadge, Andy Wilkins, Binzhong Zhou Hydrogeology Geoscience Australia: Tim Ransley (Discipline Leader), Chris Harris-Pascal, Jessica Northey, Emily Slatter Information management Bureau of Meteorology: Brendan Moran (Team Leader), Christine Panton CSIRO: Qifeng Bai, Simon Cox, Phil Davies, Geoff Hodgson Brad Lane, Ben Leighton, David Lemon, Trevor Pickett, Shane Seaton, Ramneek Singh, Matt Stenson Geoscience Australia: Matti Peljo Products CSIRO: Becky Schmidt (Products Manager), Maryam Ahmad, Clare Brandon, Heinz Buettikofer, Sonja Chandler, Karin Hosking, Allison Johnston, Maryanne McKay, Linda Merrin, Joely Taylor, Sally Tetreault-Campbell, Catherine Ticehurst Geoscience Australia: Penny Kilgour, Kathryn Owen Risk and uncertainty CSIRO: Simon Barry (Discipline Leader), Jeffrey Dambacher, Jess Ford, Keith Hayes, Geoff Hosack, Adrian Ickowicz, Warren Jin, Dan Pagendam Surface water hydrology CSIRO: Neil Viney (Discipline Leader), Santosh Aryal, Mat Gilfedder, Fazlul Karim, Lingtao Li, Dave McJannet, Jorge Luis Peña-Arancibia, Xiaogang Shi, Tom Van Niel, Jai Vaze, Bill Wang, Ang Yang, Yongqiang Zhang

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Acknowledgements

This technical product was reviewed by several groups:

 Senior Science Leaders: David Post (Projects Director), Becky Schmidt (Products Manager)  Technical Assurance Reference Group: Chaired by Peter Baker (Principal Science Advisor, Department of the Environment and Energy), this group comprises officials from the NSW, Queensland, South Australian and Victorian governments.

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Introduction

The Independent Expert Scientific Committee on Coal Seam Gas and Large Coal Mining Development (IESC) was established to provide advice to the federal Minister for the Environment on potential water-related impacts of coal seam gas (CSG) and large coal mining developments (IESC, 2015).

Bioregional assessments (BAs) are one of the key mechanisms to assist the IESC in developing this advice so that it is based on best available science and independent expert knowledge. Importantly, technical products from BAs are also expected to be made available to the public, providing the opportunity for all other interested parties, including government regulators, industry, community and the general public, to draw from a single set of accessible information. A BA is a scientific analysis, providing a baseline level of information on the ecology, hydrology, geology and hydrogeology of a bioregion with explicit assessment of the potential impacts of CSG and coal mining development on water resources.

The IESC has been involved in the development of Methodology for bioregional assessments of the impacts of coal seam gas and coal mining development on water resources (the BA methodology; Barrett et al., 2013) and has endorsed it. The BA methodology specifies how BAs should be undertaken. Broadly, a BA comprises five components of activity, as illustrated in Figure 1. Each BA will be different, due in part to regional differences, but also in response to the availability of data, information and fit-for-purpose models. Where differences occur, these are recorded, judgments exercised on what can be achieved, and an explicit record is made of the confidence in the scientific advice produced from the BA. The Bioregional Assessment Programme The Bioregional Assessment Programme is a collaboration between the Department of the Environment and Energy, the Bureau of Meteorology, CSIRO and Geoscience Australia. Other technical expertise, such as from state governments or universities, is also drawn on as required. For example, natural resource management groups and catchment management authorities identify assets that the community values by providing the list of water-dependent assets, a key input.

The Technical Programme, part of the Bioregional Assessment Programme, will undertake BAs for the following bioregions and subregions (see http://www.bioregionalassessments.gov.au/assessments for a map and further information):

 the Galilee, Cooper, Pedirka and Arckaringa subregions, within the Lake Eyre Basin bioregion  the Maranoa-Balonne-Condamine, Gwydir, Namoi and Central West subregions, within the Northern Inland Catchments bioregion  the Clarence-Moreton bioregion  the Hunter and Gloucester subregions, within the Northern Sydney Basin bioregion

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 the Sydney Basin bioregion  the Gippsland Basin bioregion.

Technical products (described in a later section) will progressively be delivered throughout the Programme.

Figure 1 Schematic diagram of the bioregional assessment methodology The methodology comprises five components, each delivering information into the bioregional assessment and building on prior components, thereby contributing to the accumulation of scientific knowledge. The small grey circles indicate activities external to the bioregional assessment. Risk identification and risk likelihoods are conducted within a bioregional assessment (as part of Component 4) and may contribute activities undertaken externally, such as risk evaluation, risk assessment and risk treatment. Source: Figure 1 in Barrett et al. (2013), © Commonwealth of Australia

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Methodologies The overall scientific and intellectual basis of the BAs is provided in the BA methodology (Barrett et al., 2013). Additional guidance is required, however, about how to apply the BA methodology to a range of subregions and bioregions. To this end, the teams undertaking the BAs have developed and documented detailed scientific submethodologies (Table 1), in the first instance, to support the consistency of their work across the BAs and, secondly, to open the approach to scrutiny, criticism and improvement through review and publication. In some instances, methodologies applied in a particular BA may differ from what is documented in the submethodologies – in this case an explanation will be supplied in the technical products of that BA. Ultimately the Programme anticipates publishing a consolidated 'operational BA methodology' with fully worked examples based on the experience and lessons learned through applying the methods to 13 bioregions and subregions.

The relationship of the submethodologies to BA components and technical products is illustrated in Figure 2. While much scientific attention is given to assembling and transforming information, particularly through the development of the numerical, conceptual and receptor impact models, integration of the overall assessment is critical to achieving the aim of the BAs. To this end, each submethodology explains how it is related to other submethodologies and what inputs and outputs are required. They also define the technical products and provide guidance on the content to be included. When this full suite of submethodologies is implemented, a BA will result in a substantial body of collated and integrated information for a subregion or bioregion, including new information about the potential impacts of coal resource development on water and water- dependent assets.

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Table 1 Methodologies Each submethodology is available online at http://data.bioregionalassessments.gov.au/submethodology/XXX, where ‘XXX’ is replaced by the code in the first column. For example, the BA methodology is available at http://data.bioregionalassessments.gov.au/submethodology/bioregional-assessment-methodology and submethodology M02 is available at http://data.bioregionalassessments.gov.au/submethodology/M02. Submethodologies might be added in the future.

Code Proposed title Summary of content bioregional- Methodology for bioregional A high-level description of the scientific and intellectual assessment- assessments of the impacts of coal basis for a consistent approach to all bioregional methodology seam gas and coal mining assessments development on water resources M02 Compiling water-dependent assets Describes the approach for determining water-dependent assets M03 Assigning receptors to water- Describes the approach for determining receptors dependent assets associated with water-dependent assets M04 Developing a coal resource Specifies the information that needs to be collected and development pathway reported about known coal and coal seam gas resources as well as current and potential resource developments M05 Developing the conceptual model Describes the development of the conceptual model of of causal pathways causal pathways, which summarises how the ‘system’ operates and articulates the potential links between coal resource development and changes to surface water or groundwater M06 Surface water modelling Describes the approach taken for surface water modelling M07 Groundwater modelling Describes the approach taken for groundwater modelling M08 Receptor impact modelling Describes how to develop receptor impact models for assessing potential impact to assets due to hydrological changes that might arise from coal resource development M09 Propagating uncertainty through Describes the approach to sensitivity analysis and models quantification of uncertainty in the modelled hydrological changes that might occur in response to coal resource development M10 Impacts and risks Describes the logical basis for analysing impact and risk M11 Systematic analysis of water- Describes the process to identify potential water-related related hazards associated with hazards from coal resource development coal resource development

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Technical products The outputs of the BAs include a suite of technical products presenting information about the ecology, hydrology, hydrogeology and geology of a bioregion and the potential impacts of CSG and coal mining developments on water resources, both above and below ground. Importantly, these technical products are available to the public, providing the opportunity for all interested parties, including community, industry and government regulators, to draw from a single set of accessible information when considering CSG and large coal mining developments in a particular area.

The information included in the technical products is specified in the BA methodology. Figure 2 shows the relationship of the technical products to BA components and submethodologies. Table 2 lists the content provided in the technical products, with cross-references to the part of the BA methodology that specifies it. The red outlines in both Figure 2 and Table 2 indicate the information included in this technical product.

Technical products are delivered as reports (PDFs). Additional material is also provided, as specified by the BA methodology:

 unencumbered data syntheses and databases  unencumbered tools, model code, procedures, routines and algorithms  unencumbered forcing, boundary condition, parameter and initial condition datasets  lineage of datasets (the origin of datasets and how they are changed as the BA progresses)  gaps in data and modelling capability.

In this context, unencumbered material is material that can be published according to conditions in the licences or any applicable legislation. All reasonable efforts were made to provide all material under a Creative Commons Attribution 3.0 Australia Licence.

Technical products, and the additional material, are available online at http://www.bioregionalassessments.gov.au.

The Bureau of Meteorology archives a copy of all datasets used in the BAs. This archive includes datasets that are too large to be stored online and datasets that are encumbered. The community can request a copy of these archived data at http://www.bioregionalassessments.gov.au.

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Figure 2 Technical products and submethodologies associated with each component of a bioregional assessment In each component (Figure 1) of a bioregional assessment, a number of technical products (coloured boxes, see also Table 2) are potentially created, depending on the availability of data and models. The light grey boxes indicate submethodologies (Table 1) that specify the approach used for each technical product. The red outline indicates this technical product. The BA methodology (Barrett et al., 2013) specifies the overall approach.

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Table 2 Technical products delivered for the Clarence-Moreton bioregion For the Clarence-Moreton Bioregional Assessment, technical products are delivered online at http://www.bioregionalassessments.gov.au, as indicated in the ‘Type’ columna. Other products – such as datasets, metadata, data visualisation and factsheets – are provided online. There is no product 1.4. Originally this product was going to describe the receptor register and application of landscape classes as per Section 3.5 of the BA methodology, but this information is now included in product 2.3 (conceptual modelling) and used in product 2.6.1 (surface water numerical modelling) and product 2.6.2 (groundwater numerical modelling). There is no product 2.4. Originally this product was going to include two- and three- dimensional representations as per Section 4.2 of the BA methodology, but these are instead included in products such as product 2.3 (conceptual modelling), product 2.6.1 (surface water numerical modelling) and product 2.6.2 (groundwater numerical modelling).

Component Product Title Section in the Typea code BA methodologyb

1.1 Context statement 2.5.1.1, 3.2 PDF, HTML Coal and coal seam gas resource 1.2 2.5.1.2, 3.3 PDF, HTML assessment Component 1: Contextual Description of the water-dependent PDF, HTML, information for the Clarence- 1.3 2.5.1.3, 3.4 asset register register Moreton bioregion Current water accounts and water 1.5 2.5.1.5 PDF, HTML quality 1.6 Data register 2.5.1.6 Register Observations analysis, statistical 2.1-2.2 2.5.2.1, 2.5.2.2 PDF, HTML analysis and interpolation 2.3 Conceptual modelling 2.5.2.3, 4.3 PDF, HTML Component 2: Model-data analysis for the Clarence- 2.5 Water balance assessment 2.5.2.4 PDF, HTML Moreton bioregion 2.6.1 Surface water numerical modelling 4.4 PDF, HTML 2.6.2 Groundwater numerical modelling 4.4 PDF, HTML 2.7 Receptor impact modelling 2.5.2.6, 4.5 Not produced Component 3 and Component 4: Impact and risk analysis for 3-4 Impact and risk analysis 5.2.1, 2.5.4, 5.3 Not produced the Clarence-Moreton bioregion Component 5: Outcome synthesis for the Clarence- 5 Outcome synthesis 2.5.5 PDF, HTML Moreton bioregion aThe types of products are as follows: ● ‘PDF’ indicates a PDF document that is developed by the Clarence-Moreton Bioregional Assessment using the structure, standards and format specified by the Programme. ● ‘HTML’ indicates the same content as in the PDF document, but delivered as webpages. ● ‘Register’ indicates controlled lists that are delivered using a variety of formats as appropriate. ● ‘Not produced’ indicates that the product was not developed. A webpage explains why and points to relevant submethodologies (Table 1).

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About this technical product The following notes are relevant only for this technical product.

 All reasonable efforts were made to provide all material under a Creative Commons Attribution 3.0 Australia Licence. All maps created as part of this BA for inclusion in this product used the Albers equal area projection with a central meridian of 151.0° East for the Clarence-Moreton bioregion and two standard parallels of –18.0° and –36.0°.  Contact [email protected] to access metadata (including copyright, attribution and licensing information) for all datasets cited or used to make figures in this product. At a later date, this information, as well as all unencumbered datasets, will be published online.  The citation details of datasets are correct to the best of the knowledge of the Bioregional Assessment Programme at the publication date of this product. Readers should use the hyperlinks provided to access the most up-to-date information about these data; where there are discrepancies, the information provided online should be considered correct. The dates used to identify Bioregional Assessment Source Datasets are the dataset’s published date. Where the published date is not available, the last updated date or created date is used. For Bioregional Assessment Derived Datasets, the created date is used. References Barrett DJ, Couch CA, Metcalfe DJ, Lytton L, Adhikary DP and Schmidt RK (2013) Methodology for bioregional assessments of the impacts of coal seam gas and coal mining development on water resources. A report prepared for the Independent Expert Scientific Committee on Coal Seam Gas and Large Coal Mining Development through the Department of the Environment. Department of the Environment, Australia. Viewed 15 March 2017, http://data.bioregionalassessments.gov.au/submethodology/bioregional-assessment- methodology.

IESC (2015) Information guidelines for the Independent Expert Scientific Committee advice on coal seam gas and large coal mining development proposals. Independent Expert Scientific Committee on Coal Seam Gas and Large Coal Mining Development, Australia. Viewed 15 March 2017, http://www.iesc.environment.gov.au/publications/information-guidelines- independent-expert-scientific-committee-advice-coal-seam-gas.

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2.5 Water balance assessment for the Clarence-Moreton bioregion

This product presents mean annual water balances for the Clarence-Moreton bioregion using results from product 2.6.1 (surface water numerical modelling) and product 2.6.2 (groundwater numerical modelling). The water balances are reported over three 30-year periods, namely 2013 to 2042, 2043 to 2072 and 2073 to 2102, during which modelled global temperature increases of 1.0, 1.5 and 2.0 °C, respectively, have been assumed.

Water balances are reported for the two potential futures considered in a bioregional assessment:

 baseline coal resource development (baseline): a future that includes all coal mines and coal seam gas (CSG) fields that are commercially producing as of December 2012  coal resource development pathway (CRDP): a future that includes all coal mines and CSG fields that are in the baseline as well as those that are expected to begin commercial production after December 2012.

The difference in results between CRDP and baseline is the change that is primarily reported in a bioregional assessment. This change is due to the additional coal resource development – all coal mines and CSG fields, including expansions of baseline operations, that are expected to begin commercial production after December 2012.

This product reports results for only those developments in the baseline and CRDP that have been modelled.

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Surface water balance terms will generally include rainfall, surface water outflow, licensed extraction and a residual term. Groundwater balance terms will generally include recharge, evapotranspiration, baseflow and change in storage. The exact set of water balance terms reported can vary from region to region.

The water balance reported here summarises volumetric changes and does not represent impacts on flow regime changes which may be more significant than changes in absolute flow volumes in some cases. For more details see product 2.6.1 (surface water numerical modelling) and product 2.6.2 (groundwater numerical modelling).

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2.5.1 Methods

Summary

The groundwater balance analysis was conducted for the entire groundwater model domain, which covers an area of 8230 km2. The groundwater balances comprise recharge, boundary flux, discharge to surface water, mining pumping, non-mining groundwater extractions, and change in storage water balance terms. The surface water balance analysis covers an area of 2942 km2 and is reported at four locations: the Richmond River above Casino, the Richmond River above Kyogle, Shannon Brook above Yorklea and Eden Creek. The surface water balances comprise rainfall, surface water outflow, and losses (including evapotranspiration and water extractions). The groundwater and surface water balances are reported for three 30-year periods (2013 to 2042, 2043 to 2072 and 2073 to 2102) for both the baseline and the coal resource development pathway (CRDP). The analysis was carried out based on 30 model realisations chosen from a total of 3877 successful simulations conducted for the sensitivity analysis reported in companion product 2.6.2 (groundwater numerical modelling) for the Clarence Moreton bioregion (Cui et al., 2016).

The water balance assessment presents a quantitative water balance for the Clarence-Moreton bioregion for both the baseline and the coal resource development pathway (CRDP). It was conducted under the guidance of companion submethodology M07 (Crosbie et al., 2016). The water balance components were derived from the outputs of the surface water modelling and the groundwater modelling that are reported in companion products 2.6.1 and 2.6.2 for the Clarence- Moreton bioregion (Gilfedder et al., 2016; Cui et al., 2016), respectively. See Section 2.6.1.5 and Section 2.6.2.8 in these products for caveats and limitations associated with the information. 2.5.1.1 Spatial and temporal extent of the water balances The Jeebropilly Mine west of Ipswich, Queensland is the only coal mine in the baseline coal resource development (baseline) for the Clarence-Moreton bioregion. In addition to this coal mine, the CRDP includes only one additional coal resource development (ACRD), which is named as West Casino Gas Project in companion product 2.3 (conceptual modelling) for the Clarence-Moreton bioregion (Raiber et al., 2016) (Figure 3). The West Casino Gas Project occurs in the central part of the Richmond river basin, while the Jeebropilly Mine is distant and hydrologically disconnected from the CSG project as described in companion product 2.3 for the Clarence-Moreton bioregion (Raiber et al., 2016). Thus, the water balance analysis, surface water modelling, and groundwater modelling was only carried out for the Richmond river basin area.

A groundwater model has been developed to assess the potential impacts of the West Casino Gas Project on the groundwater system and associated groundwater-dependent ecosystems in companion product 2.6.2 for the Clarence-Moreton bioregion (Cui et al., 2016). This water balance analysis is based on the groundwater modelling results. The groundwater balance analysis was conducted for the entire groundwater model domain in order to capture any possible changes in water balance due to the West Casino Gas Project. The groundwater model covers an area of 8230 km2 and mostly follows the boundaries of the Richmond river basin with deviations in some

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areas as outlined in companion product 2.3 (conceptual modelling) for the Clarence-Moreton bioregion (Raiber et al., 2016). The groundwater model boundary is shown in Figure 3. A more detailed description of the groundwater model is found in companion product 2.6.2 for the Clarence-Moreton bioregion (Cui et al., 2016).

A surface water Australian Water Resources Assessment landscape model (AWRA-L) has been developed to assess the potential impacts of the West Casino Gas Project on the surface water system (see companion product 2.6.1 for the Clarence-Moreton bioregion (Gilfedder et al., 2016)). The surface water balance analysis is reported at three locations which are either in or very close to the West Casino Gas Project: Eden Creek (model node CLM002), Shannon Brook above Yorklea (model node CLM007), and Richmond River above Casino (model node CLM008) (Figure 3). It is also reported for the Richmond River above Kyogle (model node CLM014) to ensure that any groundwater impacts propagating north along the Richmond river valley are estimated. A more detailed description of the surface water model is found in companion product 2.6.1 for the Clarence-Moreton bioregion (Gilfedder et al., 2016).

The water balances are reported for three 30-year periods (2013 to 2042, 2043 to 2072 and 2073 to 2102) for both the baseline and CRDP. These three periods align with temperature increases of 1.0, 1.5 and 2.0 °C from current, under a future climate projection derived from the CSIRO-Mk3.0 global climate model (GCM) (Viney, 2016). Only a single future climate time series was used during the modelling for water balance analysis. The climate time series was generated by concatenating the 30-year series (1983–2012) three times, and scaled by a median climate change projection.

The time to maximum hydrological change will be different for different water balance terms such as surface water outflow and storage change, which means that at the bioregion level there is not a single point in time for which a maximum change on water balance can be constructed. Thus, the water balance changes are not reported as a maximum and its associated occurring time.

12 | Water balance assessment for the Clarence-Moreton bioregion

Figure 3 Location of model nodes for surface water balance terms for the Clarence-Moreton bioregion ACRD = additional coal resource development Data: Bioregional Assessment Programme (Dataset 1)

Water balance assessment for the Clarence-Moreton bioregion | 13

2.5.1.2 Water balance uncertainty The components of the water balance are not included in the uncertainty analysis reported in companion product 2.6.1 (Gilfedder et al., 2016) and 2.6.2 (Cui et al., 2016) for the Clarence-Moreton bioregion. The water balance analysis was carried out based on 30 model simulations selected from a total of 3877 simulations conducted for the sensitivity analysis reported in companion product 2.6.2 (groundwater numerical modelling) for the Clarence-Moreton bioregion (Cui et al., 2016). The sample size of 30 was used because it is commonly considered as the threshold sample size separating small-sample statistics from large- sample statistics (Davis, 2002). While the 30 samples will not provide the rigorous uncertainty analysis that is presented in companion product 2.6.1 (Gilfedder et al., 2016) and product 2.6.2 (Cui et al., 2016) for the Clarence-Moreton bioregion, it is expected to provide a statistically significant estimate of the 10th, 50th and 90th percentiles of the water balance components. Losses are not able to be included in the estimation of water balance uncertainty because they would not form part of the hydrological response variables used should any impact and risk analysis be conducted.

The selection of suitable simulations and subsequent output analysis involved the following steps:

1. Filter models using the forecast water production. Only models with a median annual water production that is within the range from one-tenth of the forecast volume to ten times the forecast volume were used for further analysis. 2. Compute the head objective function (sum of squared residuals) using the observed heads described in companion product 2.6.2 for the Clarence-Moreton bioregion (Cui et al., 2016). 3. Compute the baseflow objective function (sum of squared residuals) using estimated baseflow at the river stage gauge site near Casino (CLM008) (Figure 3). 4. Rank the models based on the sum of the two normalised components of the objective function described in step 2 and step 3. 5. Conduct a statistical summary analysis using the top 30 models derived in step 4.

The computing approaches for various water balance terms are summarised in Table 3 and Table 4.

Table 3 Computing approaches of water balance terms in the surface water model for the Clarence-Moreton bioregion

Water balance term Computing approach Rainfall Measured rainfall modified using scaling factors from global climate models (GCMs) Surface water outflow From AWRA-L model Licensed extractions AWRA-L does not model extractions CSG produced water Any discharge to streams is subject to stringent control and could not be included in the AWRA-L model since timing and volume is not known. Losses Rainfall minus surface water outflow. This includes evapotranspiration, and would also include water extractions since AWRA-L does not model them explicitly AWRA-L is the Australian Water Resources Assessment landscape model

14 | Water balance assessment for the Clarence-Moreton bioregion

Table 4 Computing approaches of water balance terms in the groundwater model for the Clarence-Moreton bioregion

Water balance term Computing approach

Recharge (diffuse) From the Recharge Package of MODFLOW

Recharge (streams) From the River Package of MODFLOW

GHB boundary From the General-Head Boundary Package of MODFLOW

Discharge (surface water) The perennial streams were explicitly simulated in the groundwater model using the River Package of MODFLOW. Other surface water features, such as local intermittent streams and swamps, were lumped together and implicitly simulated using the Drain Package of MODFLOW. Thus, discharge to the surface water represents the sum of the discharge components of these two packages. Non-CSG bores From the MNW2 Package of MODFLOW that was implemented in accordance with the licensed extractions. CSG wells The CSG water pumping process was simulated by the Drain Package of MODFLOW. Thus, the water balance term is from the component representing CSG wells in the Drain Package. Storage change Directly from the storage component in MODFLOW water balance output CSG = coal seam gas

References Crosbie R, Peeters L and Carey H (2016) Groundwater modelling. Submethodology M07 from the Bioregional Assessment Technical Programme. Department of the Environment and Energy, Bureau of Meteorology, CSIRO and Geoscience Australia, Australia. http://data.bioregionalassessments.gov.au/submethodology/M07.

Cui T, Peeters L, Rassam D, Raiber M, Crosbie R, Gilfedder M, Pickett T, Hartcher M, Marvanek S and Bruce C (2016) Groundwater numerical modelling for the Clarence-Moreton Bioregion. Product 2.6.2 from the Clarence-Moreton Bioregional Assessment. Department of the Environment and Energy, Bureau of Meteorology, CSIRO and Geoscience Australia, Australia. http://data.bioregionalassessments.gov.au/product/CLM/CLM/2.6.2.

Davis JC (2002) Statistics and data analysis in geology. John Wiley and Sons Ltd, New York.

Gilfedder M, McJannet D, Wang B, Peeters L, Zhang Y, Peña-Arancibia J, Shi X, Marvanek S, Viney N, Hartcher M, Pickett T, Crosbie R, Yang A, Vaze J, Lingtao L, Cui T, Raiber M and Rassam D (2016) Surface water numerical modelling for the Clarence-Moreton bioregion. Product 2.6.1 from the Clarence-Moreton Bioregional Assessment. Department of the Environment and Energy, Bureau of Meteorology, CSIRO and Geoscience Australia, Australia. http://data.bioregionalassessments.gov.au/product/CLM/CLM/2.6.1.

Raiber M, Murray J, Bruce C, Rassam D, Ebner B, Henderson B, O’Grady T, Gilfedder M and Cui T (2016) Conceptual modelling for the Clarence-Moreton bioregion. Product 2.3 from the Clarence-Moreton Bioregional Assessment. Department of the Environment and Energy, Bureau of Meteorology, CSIRO and Geoscience Australia, Australia. http://data.bioregionalassessments.gov.au/product/CLM/CLM/2.3.

Water balance assessment for the Clarence-Moreton bioregion | 15

Viney N (2016) Surface water modelling. Submethodology M06 from the Bioregional Assessment Technical Programme. Department of the Environment and Energy, Bureau of Meteorology, CSIRO and Geoscience Australia, Australia. http://data.bioregionalassessments.gov.au/submethodology/M06. Datasets Dataset 1 Bioregional Assessment Programme (2015) Data for river stage interpolation in the CLM groundwater model. Bioregional Assessment Derived Dataset. Viewed 19 February 2016, http://data.bioregionalassessments.gov.au/dataset/c486f991-fc71-44c5-974f-85913ce82faf.

16 | Water balance assessment for the Clarence-Moreton bioregion

2.5.2 The water balances

Summary

The surface water balance analysis is reported at four model nodes: the Richmond River above Casino, the Richmond River above Kyogle, Shannon Brook above Yorklea and Eden Creek. It is reported for three consecutive 30-year periods, each with different rainfall inputs to reflect modelled varying climate signal. The median change at all four model nodes was essentially zero (less than 0.05 GL total) in surface water balance for each of the 30-year periods (2013 to 2042, 2043 to 2072 and 2073 to 2102). There are insignificant changes in baseflow during the three 30-year periods.

Based on the current groundwater model conceptualisation, groundwater storage exhibits a future decline even without the impacts of the West Casino Gas Project, although the median annual reduction is well below 0.5% of the corresponding median annual recharge for all the three reporting periods. This can be a result of climate change, extraction for irrigation and other usage. Water usage by the West Casino Gas Project mainly occurs between 2013 and 2042 with a median mean annual pumping of 328 ML/year. An additional 321 ML/year reduction in groundwater storage occurs due to the West Casino Gas Project from 2013 to 2042. A very small impact is also seen in the discharge component to surface water to compensate for coal seam gas (CSG) water production. No other impact can be identified for the other water balance components.

2.5.2.1 Water balance based on the AWRA-L model Surface water balances are reported for three consecutive 30-year periods, each with different rainfall inputs to reflect a temporally trended climate signal. Licensed extractions from surface water for non-mining uses are not reported because they are unable to be represented in the Australian Water Resources Assessment landscape model (AWRA-L). Such extraction can be modelled using the Australian Water Resources Assessment river model (AWRA-R), however in the absence of significant regulation and consumptive water use, AWRA-R has not been used in this study. The impact of licensed extractions of groundwater for CSG is reflected in changes in the upward flow from the deeper groundwater system as modelled in the groundwater model. The impact of the additional coal resource development (the West Casino Gas Project), calculated as difference between the coal resource development pathway (CRDP) and the baseline (presented in Table 5 to Table 9), reflects the impacts of CSG development only, as the climate signal is identical in both modelling runs. The changes in corresponding values over the three reporting periods encompass the effects of both climate and the coal resource development. Note that the values in the difference column are calculated individually for each of the 30 model runs, and the summary differences presented (i.e. median of the differences, not difference of the medians). The median, 10th and 90th percentile of water balance components derived from the selected 30 AWRA-L model runs are presented in this section.

Water balance assessment for the Clarence-Moreton bioregion | 17

This section provides summaries of the total water balance calculated at four surface water locations in the Richmond river basin for each of the three 30-year periods. These locations are:

 Eden Creek above its confluence with the Richmond River (model node CLM002)  Shannon Brook above Yorklea (model node CLM007)  Richmond River above Casino (model node CLM008)  Richmond River above Kyogle (model node CLM014).

The effect of climate change in the water balance for the Richmond river basin is very small given the projected climate signal in the current model. There is a decreasing trend in the rainfall which translates into a decreasing trend in the surface water outflow and groundwater recharge. However, the magnitude of the change is very small with less than 2% decrease in rainfall and surface water outflow and slightly more than 1% decrease in groundwater recharge when the 2073 to 2102 period is compared to the 2013 to 2042 period for the baseline. 2.5.2.1.1 Water balance for Eden Creek (model node CLM002) The catchment area above model node CLM002 is 696 km2 and is within the West Casino Gas Project extent. The difference in the modelled water balance between the CRDP and the baseline at Eden Creek is in the total surface water outflow over each of the three 30-year periods (Table 5). Note that differences of less than 0.05 GL will appear as 0.0 GL in the table (0.05 GL over 30-year period is less than 2 ML/year).

Period Water balance term Total under the Total under the coal Difference for entire baseline resource development period (GL) pathway (GL) (GL) 2013 to 2042 Rainfall 22,404 22,404 0 Surface water outflow 5,600 (4,020; 6,678) 5,600 (4,020; 6,678) 0.0 (0.0; 0.0) Licensed extractions NM NM NM Losses 16,804 16,804 0 2043 to 2072 Rainfall 22,201 22,201 0 Surface water outflow 5,563 (3,992; 6,625) 5,563 (3,992; 6,625) 0.0 (0.0; –0.1) Licensed extractions NM NM NM Losses 16,638 16,638 0 2073 to 2102 Rainfall 21,998 21,998 0 Surface water outflow 5,527 (3,978; 6,571) 5,527 (3,978; 6,571) 0.0 (0.0; –0.1) Licensed extractions NM NM NM Losses 16,471 16,471 0 Three numbers are provided for surface water outflow. The first number is the median, and the 10th and 90th percentile numbers follow in brackets. NM = data not modelled Data: Bioregional Assessment Programme (Dataset 1, Dataset 2)

18 | Water balance assessment for the Clarence-Moreton bioregion

2.5.2.1.2 Water balance for Shannon Brook above Yorklea (model node CLM007) The catchment area above model node CLM007 is 498 km2 and is within the West Casino Gas Project extent. The difference in the modelled water balance between the CRDP and the baseline for Shannon Brook is the total surface water outflow over each of the three 30-year periods (Table 6). The difference was less than 0.2 GL for all three of the 30-year periods. Note that differences of less than 0.05 GL will appear as 0.0 GL in the table (0.05 GL over 30-year period is less than 2 ML/year).

Period Water balance term Total under the Total under the coal Difference between baseline resource development CRDP and baseline for (GL) pathway entire period (GL) (GL) 2013 to 2042 Rainfall 15,977 15,977 0 Surface water outflow 4,628 (3,361; 5,364) 4,628 (3,361; 5,364) 0.0 (0.0; 0.0) Licensed extractions NM NM NM Losses 11,349 11,349 0 2043 to 2072 Rainfall 15,828 15,828 0 Surface water outflow 4,576 (3,333; 5,300) 4,576 (3,333; 5,300) 0.0 (0.0; –0.2) Licensed extractions NM NM NM Losses 11,252 11,252 0 2073 to 2102 Rainfall 15,679 15,679 0 Surface water outflow 4,529 (3,314; 5,226) 4,529 (3,314; 5,226) 0.0 (0.0; –0.1) Licensed extractions NM NM NM Losses 11,150 11,150 0 Three numbers are provided for surface water outflow. The first number is the median, and the 10th and 90th percentile numbers follow in brackets. NM = data not modelled Data: Bioregional Assessment Programme (Dataset 1, Dataset 2)

2.5.2.1.3 Water balance for Richmond River above Casino (model node CLM008) The catchment area above model node CLM008 is 1874 km2. The difference in the modelled water balance between the CRDP and the baseline for the Richmond River above Casino is in the surface water outflow over each of the three 30-year periods (Table 7). The difference was less than 0.05 GL for all three of the 30-year periods. Note that differences of less than 0.05 GL will appear as 0.0 GL in the table (0.05 GL over 30-year period is less than 2 ML/year).

Water balance assessment for the Clarence-Moreton bioregion | 19

Period Water balance term Total under the Total under the coal Difference between baseline resource development CRDP and baseline for (GL) pathway entire period (GL) (GL) 2013 to 2042 Rainfall 63,120 63,120 0 Surface water outflow 17,284 (11,057; 21,620) 17,284 (11,057; 21,620) 0.0 (0.0; 0.0) Licensed extractions NM NM NM Losses 45,836 45,836 0 2043 to 2072 Rainfall 62,552 62,552 0 Surface water outflow 17,122 (10,938; 21,361) 17,122 (10,937; 21,361) 0.0 (0.0; 0.0) Licensed extractions NM NM NM Losses 45,430 45,430 0 2073 to 2102 Rainfall 61,984 61,984 0 Surface water outflow 16,983 (10,880; 21,114) 16,983 (10,880; 21,114) 0.0 (0.0; 0.0) Licensed extractions NM NM NM Losses 45,001 45,001 0 Three numbers are provided for surface water outflow. The first number is the median, and the 10th and 90th percentile numbers follow in brackets. NM = data not modelled Data: Bioregional Assessment Programme (Dataset 1, Dataset 2)

2.5.2.1.4 Water balance for Richmond River above Kyogle (model node CLM014) The catchment area above model node CLM014 is 903 km2 and is upstream of the West Casino Gas Project extent. It has been included to check if there are any predicted impacts further north along the main Richmond river valley, beyond the West Casino Gas Project extent itself. The comparison of the modelled water balance between the CRDP and the baseline for the surface water outflow from the Richmond River above Kyogle shows that there is almost no difference for the 30-year period 2013 to 2042 (Table 8), and no increase in the subsequent two 30-year periods (Table 8). This indicates that there are no significant modelled changes in baseflow. Note that differences of <0.05 GL will appear as 0.0 GL in the table (0.05 GL over 30-year period is less than 2 ML/year). The results indicate that the groundwater drawdown due to the West Casino Gas Project does not propagate as far upstream as this catchment.

20 | Water balance assessment for the Clarence-Moreton bioregion

Period Water balance term Total under the Total under the coal Difference between baseline resource development CRDP and baseline for (GL) pathway entire period (GL) (GL) 2013 to 2042 Rainfall 31,862 31,862 0 Surface water outflow 9,827 (5,592; 12,415) 9,827 (5,592; 12,415) 0.0 (0.0; 0.0) Licensed extractions NM NM NM Losses 22,035 22,035 0 2043 to 2072 Rainfall 31,582 31,582 0 Surface water outflow 9,762 (5,537; 12,275) 9,762 (5,537; 12,275) 0.0 (0.0; 0.0) Licensed extractions NM NM NM Losses 21,820 21,820 0 2073 to 2102 Rainfall 31,303 31,303 0 Surface water outflow 9,684 (5,493; 12,134) 9,684 (5,493; 12,134) 0.0 (0.0; 0.0) Licensed extractions NM NM NM Losses 21,619 21,619 0 Three numbers are provided for surface water outflow. The first number is the median, and the 10th and 90th percentile numbers follow in brackets. NM = data not modelled Data: Bioregional Assessment Programme (Dataset 1, Dataset 2)

2.5.2.2 Water balance based on groundwater model The water balance is reported for the entire groundwater model domain and is based on the modelling results from the top 30 best-fit models (Bioregional Assessment Programme, Dataset 4). The water balance is summarised in Table 9 for the three reporting periods of 2013 to 2042, 2043 to 2072 and 2073 to 2102, respectively. For each time period the 10th, 50th (median) and 90th percentiles of mean annual values of different water balance components are reported for both the baseline and CRDP. The net impact of the West Casino Gas Project is the difference between the results for the CRDP model and the baseline, and is also reported in the tables. Downwards, upwards and up-down arrows are used to indicate inflow, outflow and inflow/outflow water balance components, respectively.

Based on the current groundwater model conceptualisation, groundwater storage exhibits a future decline even without the impacts of the West Casino Gas Project, although the median annual reduction is well below 0.5% of the corresponding median annual recharge for all the three reporting periods. This can be partly attributed to the climate change signal used in the model; it can also be a result of extraction for irrigation and other usage. Overall, diffuse recharge from precipitation and discharge to surface water systems are the two dominant water balance components for both the baseline and CRDP. Among the 30 sets of modelling results, only the net balance of the General-Head Boundary (GHB) (a package used to simulate head-dependent flux boundaries in MODFLOW) (Harbaugh, 2005) varies from discharge to recharge. This implies that the adopted observations do not constrain the GHB related parameters. Water balance

Water balance assessment for the Clarence-Moreton bioregion | 21

components associated with the GHB boundary are less reliable than other components. Additional observations are required to improve the estimate of flux exchange between the model domain and its surrounding aquifers.

Groundwater extraction due to the West Casino Gas Project mainly occurs between 2013 and 2042 with a median mean annual pumping of 328 ML/year. The median additional mean annual reduction in storage due to the West Casino Gas Project from 2013 to 2042 is 327 ML/year (6.62% of the median mean annual storage change for the baseline). A very minor change is also seen in the discharge component to surface water (Table 9) to compensate for CSG water production. No other changes can be identified for the other water balance components. The water production by the West Casino Gas Project reduces to 58 ML/year (median mean annual extraction) for the second reporting period (Table 9). However, the median mean annual discharge difference grows from 3 to 24 ML/year due to the time lag. The storage change difference is mitigated to some extent through the reduction of discharge component to surface water from 2043 to 2072. The impact on the discharge to the surface water continues until the end of the simulation (Table 9).

The overall change in groundwater balance due to the West Casino Gas Project over the entire model domain is very minor based on the modelling in companion product 2.6.2 for the Clarence-Moreton bioregion (Cui et al., 2016) given the current model conceptualisation. For example, for the first reporting period (2013 to 2042), the median mean annual extraction due to the West Casino Gas Project only corresponds to 0.02% of the median mean annual recharge of the groundwater model domain (Table 9). There, however, can possibly be a more significant change in groundwater water balance components on a local scale close to the CSG development, especially during a dry period when more groundwater is required for other usage such as irrigation. Given the current regional model, a refined model could be developed in order to evaluate the potential impact on a local scale.

22 | Water balance assessment for the Clarence-Moreton bioregion

Table 9 Mean annual groundwater balance for the entire groundwater model domain for the three reporting periods in the Clarence-Moreton bioregion (ML/year) aThe net impact of the additional coal resource development (ACRD) is defined as the difference between results for the coal resource development pathway (CRDP) and the baseline. Note that the difference is calculated individually for each of the 30 model runs because the median under baseline may not correspond to the same realisation with the median under CRDP. The difference column is the summary of individual differences (i.e. median of the differences, not difference of the medians).

Period Water balance term Under baseline Under CRDP Differencea

↓Recharge (diffuse) 1,600,025 (859,946; 1,600,025 (859,946; 0 (0; 0) 2,621,302) 2,621,302) ↓Recharge (streams) 11,628 (4,043; 55,712) 11,628 (4,043; 55,712) 0 (0; 1)

↕GHB 8,592 (–47,758; 117,411) 8,592 (–47,758; 117,411) 0 (0; 0)

↑Discharge (surface 1,607,220 (920,573; 1,607,215 (920,359; –3 (–38; 0) water) 2,643,897) 2,643,851)

2013 to 2042 2013 to ↑Non-CSG bores 11,059 (10,678; 11,187) 11,059 (10,677; 11,187) 0 (0; 0)

↑CSG wells NA 328 (88; 651) NA

Storage change –5,161 (–9,271; –2,968) –5,482 (–9,671; –3,130) –327 (–613; –82)

↓Recharge (diffuse) 1,590,460 (854,806; 1,590,460 (854,806; 0 (0; 0) 2,605,634) 2,605,634) ↓Recharge (streams) 11,659 (4,065; 55,745) 11,660 (4,065; 55,747) 0 (0; 3)

↕GHB 9,053 (–46,935; 118,597) 9,053 (–46,935; 118,597) 0 (0; 0)

↑Discharge (surface 1,597,290 (915,104; 1,597,240 (914,749; –24 (–123; –1) water) 2,628,197) 2,628,098)

2043 to 2072 2043 to ↑Non-CSG bores 11,058 (10,671; 11,186) 11,058 (10,670; 11,186) 0 (0; 0)

↑CSG wells NA 58 (16; 121) NA

Storage change –4,216 (–9,073; –2,437) –4,272 (–9,111; –2,425) –31 (–80; 86)

↓Recharge (diffuse) 1,579,535 (848,934; 1,579,535 (848,934; 0 (0; 0) 2,587,734) 2,587,734) ↓Recharge (streams) 11,681 (4,083; 55,766) 11,682 (4,083; 55,769) 0 (0; 2)

↕GHB 9,462 (–46,130; 119,759) 9,462 (–46,130; 119,759) 0 (0; 0)

↑Discharge (surface 1,587,365 (909,639; 1,587,300 (909,561; –25 (–83; –2) water) 2,612,398) 2,612,361)

2073 to 2102 2073 to ↑Non-CSG bores 11,055 (10,664; 11,183) 11,055 (10,663; 11,183) 0 (0; 0)

↑CSG wells NA 0 (0; 0) NA

Storage change –4,723 (–10,163; –2,478) –4,721 (–10,158; –2,440) 25 (2; 87) The first number is the median, and the 10th and 90th percentile numbers follow in brackets. Water balance terms impacted by the West Casino Gas Project are shown in bold. GHB = general-head boundary CSG = coal seam gas NA = data not available ↓: inflow; ↑: outflow; ↕: inflow and outflow Data: Bioregional Assessment Programme (Dataset 3, Dataset 4)

Water balance assessment for the Clarence-Moreton bioregion | 23

2.5.2.3 Gaps Limitations lie in some parameters and the implementation of some stresses, such as localized discharge and evapotranspiration, in the groundwater model. Surface water relevant inputs, such as recharge and river stage, over the three reporting periods only reflect changes due to a single varying climate signal. Thus, the uncertainty in the climate signal is not taken into account in the current analysis. In order to improve model stability and reduce model runtime for a feasible sensitivity analysis, evapotranspiration was not explicitly simulated in the groundwater model. The estimated recharge component may compensate for the ignorance of evapotranspiration to some extent. Only the perennial reaches of the streams within the model domain were simulated directly using the River Package in MODFLOW. This simplification may underestimate stream recharge to the groundwater system. The dual-phase flow process near CSG wells was not modelled in the current project. Previous studies (Moore et al., 2013; Moore et al., 2014; Herckenrath et al., 2015) have shown that the omitting of dual-phase flow overestimates drawdown impact, especially for prediction near CSG wells, depending on hydraulic properties, development plans and simulation time. For example, Moore et al. (2015) reported a drawdown overproduction of 15 m at a distance of 7 km from the well extraction centre at a simulation time of 20 years within the targeted coal seam formation in their model. The Assessment team believe that storage change due to CSG development is also overestimated to some extent, although the impact on water balance analysis was not directly investigated in these studies. In addition, assumptions, limitations and gaps listed in companion products 2.6.1 (surface water numerical modelling) (Gilfedder et al., 2016) and 2.6.2 (groundwater numerical modelling) (Cui et al., 2016) for the Clarence-Moreton bioregion also have an impact on water balance analysis. References Cui T, Peeters L, Rassam D, Raiber M, Crosbie R, Gilfedder M, Pickett T, Hartcher M, Marvanek S and Bruce C (2016) Groundwater numerical modelling for the Clarence-Moreton Bioregion. Product 2.6.2 from the Clarence-Moreton Bioregional Assessment. Department of the Environment and Energy, Bureau of Meteorology, CSIRO and Geoscience Australia, Australia. http://data.bioregionalassessments.gov.au/product/CLM/CLM/2.6.2.

Harbaugh AW (2005) MODFLOW-2005, The U.S. Geological Survey modular ground-water model— the Ground-Water Flow Process: U.S. Geological Survey Techniques and Methods 6-A16. Viewed 9 February 2016, http://pubs.usgs.gov/tm/2005/tm6A16/.

Herckenrath D, Doherty JE, and Panday S (2015) Incorporating the effect of gas in modelling the impact of CBM extraction on regional groundwater systems. Journal of Hydrology, 523, 587– 601. doi:10.1016/j.jhydrol.2015.02.012.

24 | Water balance assessment for the Clarence-Moreton bioregion

Moore CR, Doherty J, Howell S, and Erriah L (2015) Some Challenges Posed by Coal Bed Methane Regional Assessment Modeling. Groundwater, 53(5), 737–747. doi:10.1111/gwat.12276.

Moore CR, Doherty JE, Howell S, Erriah L, de Verteuil D, and Cui T (2013) Challenges for upscaling hydraulic properties and processes in the Coal Seam Gas context. CSIRO, Australia. Datasets Dataset 1 Bioregional Assessment Programme (2016) CLM Surface water model outflows for model nodes in the Richmond river basin. Bioregional Assessment Derived Dataset. Viewed 11 February 2016, http://data.bioregionalassessments.gov.au/dataset/1bfe9d35-62aa-4940- b9a8-5b05361e9932.

Dataset 2 Bioregional Assessment Programme (2016) CLM Modelled rainfall predictions. Bioregional Assessment Derived Dataset. Viewed 11 February 2016, http://data.bioregionalassessments.gov.au/dataset/75ab5801-cb68-4d90-a13b- 9df1cdba10cc.

Dataset 3 Bioregional Assessment Programme (2015) CLM groundwater model V1. Bioregional Assessment Derived Dataset. Viewed 30 November 2015, http://data.bioregionalassessments.gov.au/dataset/2acf0342-956e-430f-9142- cf64d2b9d118.

Dataset 4 Bioregional Assessment Programme (2016) CLM Groundwater balance analysis. Bioregional Assessment Derived Dataset. Viewed 2 February 2016, https://data.bioregionalassessments.gov.au/datastore/dataset/a9f11fcd-b728-4a48-ab89- 1689bc8d888f.

Water balance assessment for the Clarence-Moreton bioregion | 25 Glossary

Glossary The register of terms and definitions used in the Bioregional Assessment Programme is available

Moreton

- online at http://environment.data.gov.au/def/ba/glossary (note that terms and definitions are

ce respectively listed under the 'Name' and 'Description' columns in this register). This register is a list of terms, which are the preferred descriptors for concepts. Other properties are included for each term, including licence information, source of definition and date of approval. Semantic

Claren

relationships (such as hierarchical relationships) are formalised for some terms, as well as linkages to other terms in related vocabularies.

additional coal resource development: all coal mines and coal seam gas (CSG) fields, including expansions of baseline operations, that are expected to begin commercial production after December 2012

aquifer: rock or sediment in a formation, group of formations, or part of a formation that is

data analysis for the - saturated and sufficiently permeable to transmit quantities of water to bores and springs

asset: an entity that has value to the community and, for bioregional assessment purposes, is associated with a subregion or bioregion. Technically, an asset is a store of value and may be managed and/or used to maintain and/or produce further value. Each asset will have many values associated with it and they can be measured from a range of perspectives; for example, the values of a wetland can be measured from ecological, sociocultural and economic perspectives.

Component 2: Model baseline coal resource development: a future that includes all coal mines and coal seam gas (CSG) fields that are commercially producing as of December 2012

bioregion: a geographic land area within which coal seam gas (CSG) and/or coal mining developments are taking place, or could take place, and for which bioregional assessments (BAs) are conducted

bioregional assessment: a scientific analysis of the ecology, hydrology, geology and hydrogeology of a bioregion, with explicit assessment of the potential direct, indirect and cumulative impacts of coal seam gas and coal mining development on water resources. The central purpose of bioregional assessments is to analyse the impacts and risks associated with changes to water- dependent assets that arise in response to current and future pathways of coal seam gas and coal mining development.

coal resource development pathway: a future that includes all coal mines and coal seam gas (CSG) fields that are in the baseline as well as those that are expected to begin commercial production after December 2012

component: for the purposes of Impact Modes and Effects Analysis (IMEA), a group of activities associated with a coal seam gas (CSG) operation or coal mine. For example, components during the development life-cycle stage of a coal mine include developing the mine infrastructure, the open pit, surface facilities and underground facilities. Components are grouped into life-cycle stages.

context: the circumstances that form the setting for an event, statement or idea

26 | Water balance assessment for the Clarence-Moreton bioregion Glossary dataset: a collection of data in files, in databases or delivered by services that comprise a related 2: Model Component set of information. Datasets may be spatial (e.g. a shape file or geodatabase or a Web Feature Service) or aspatial (e.g. an Access database, a list of people or a model configuration file). discharge: water that moves from a groundwater body to the ground surface or surface water body (e.g. a river or lake) drawdown: a lowering of the groundwater level (caused, for example, by pumping). In the bioregional assessment (BA) context this is reported as the difference in groundwater level - data analysis for the analysis data between two potential futures considered in BAs: baseline coal resource development (baseline) and the coal resource development pathway (CRDP). The difference in drawdown between CRDP and baseline is due to the additional coal resource development (ACRD). Drawdown under the baseline is relative to drawdown with no coal resource development; likewise, drawdown under the CRDP is relative to drawdown with no coal resource development. ecosystem: a dynamic complex of plant, animal, and micro-organism communities and their non-

living environment interacting as a functional unit. Note: ecosystems include those that are Clarence human-influenced such as rural and urban ecosystems. effect: for the purposes of Impact Modes and Effects Analysis (IMEA), change in the quantity or

- quality of surface water or groundwater. An effect is a specific type of an impact (any change Moreton resulting from prior events). extraction: the removal of water for use from waterways or aquifers (including storages) by

pumping or gravity channels formation: rock layers that have common physical characteristics (lithology) deposited during a specific period of geological time groundwater: water occurring naturally below ground level (whether in an aquifer or other low permeability material), or water occurring at a place below ground that has been pumped, diverted or released to that place for storage there. This does not include water held in underground tanks, pipes or other works. groundwater recharge: replenishment of groundwater by natural infiltration of surface water (precipitation, runoff), or artificially via infiltration lakes or injection groundwater system: see water system hydrogeology: the study of groundwater, including flow in aquifers, groundwater resource evaluation, and the chemistry of interactions between water and rock impact: a change resulting from prior events, at any stage in a chain of events or a causal pathway. An impact might be equivalent to an effect (change in the quality or quantity of surface water or groundwater), or it might be a change resulting from those effects (for example, ecological changes that result from hydrological changes). inflow: surface water runoff and deep drainage to groundwater (groundwater recharge) and transfers into the water system (both surface water and groundwater) for a defined area

Water balance assessment for the Clarence-Moreton bioregion | 27 Glossary

recharge: see groundwater recharge

sensitivity: the degree to which the output of a model (numerical or otherwise) responds to

Moreton uncertainty in a model input

- ce source dataset: a pre-existing dataset sourced from outside the Bioregional Assessment Programme. This includes data sourced from the Programme partner organisations.

Claren subregion: an identified area wholly contained within a bioregion that enables convenient presentation of outputs of a bioregional assessment (BA)

surface water: water that flows over land and in watercourses or artificial channels and can be captured, stored and supplemented from dams and reservoirs

uncertainty: the state, even partial, of deficiency of information related to understanding or knowledge of an event, its consequence, or likelihood. For the purposes of bioregional

data analysis for the - assessments, uncertainty includes: the variation caused by natural fluctuations or heterogeneity; the incomplete knowledge or understanding of the system under consideration; and the simplification or abstraction of the system in the conceptual and numerical models.

water-dependent asset: an asset potentially impacted, either positively or negatively, by changes in the groundwater and/or surface water regime due to coal resource development

water system: a system that is hydrologically connected and described at the level desired for management purposes (e.g. subcatchment, catchment, basin or drainage division, or groundwater

Component 2: Model management unit, subaquifer, aquifer, groundwater basin)

well: typically a narrow diameter hole drilled into the earth for the purposes of exploring, evaluating or recovering various natural resources, such as hydrocarbons (oil and gas) or water. As part of the drilling and construction process the well can be encased by materials such as steel and cement, or it may be uncased. Wells are sometimes known as a ‘wellbore’.

28 | Water balance assessment for the Clarence-Moreton bioregion Glossary

2: Model Component

data analysis for the analysis data

Clarence

Moreton

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